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FlashSort.js
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FlashSort.js
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/**
* Flashsort is a distribution sorting algorithm showing linear
* computational complexity O(n) for uniformly distributed
* data sets and relatively little additional memory requirement.
*
* Wikipedia: https://en.wikipedia.org/wiki/Flashsort
*/
function flashSort (arr) {
let max = 0; let min = arr[0]
const n = arr.length
const m = ~~(0.45 * n)
const l = new Array(m)
for (let i = 1; i < n; ++i) {
if (arr[i] < min) {
min = arr[i]
}
if (arr[i] > arr[max]) {
max = i
}
}
if (min === arr[max]) {
return arr
}
const c1 = (m - 1) / (arr[max] - min)
for (let k = 0; k < m; k++) {
l[k] = 0
}
for (let j = 0; j < n; ++j) {
const k = ~~(c1 * (arr[j] - min))
++l[k]
}
for (let p = 1; p < m; ++p) {
l[p] = l[p] + l[p - 1]
}
let hold = arr[max]
arr[max] = arr[0]
arr[0] = hold
// permutation
let move = 0; let t; let flash
let j = 0
let k = m - 1
while (move < (n - 1)) {
while (j > (l[k] - 1)) {
++j
k = ~~(c1 * (arr[j] - min))
}
if (k < 0) break
flash = arr[j]
while (j !== l[k]) {
k = ~~(c1 * (flash - min))
hold = arr[t = --l[k]]
arr[t] = flash
flash = hold
++move
}
}
// insertion
for (j = 1; j < n; j++) {
hold = arr[j]
let i = j - 1
while (i >= 0 && arr[i] > hold) {
arr[i + 1] = arr[i--]
}
arr[i + 1] = hold
}
return arr
}
/**
* Implementation of Flash Sort
*/
const array = [3, 0, 2, 5, -1, 4, 1, -2]
// Before Sort
console.log('\n- Before Sort | Implementation of Flash Sort -')
console.log(array)
// After Sort
console.log('- After Sort | Implementation of Flash Sort -')
console.log(flashSort(array))
console.log('\n')